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Karolis Juodelė's user avatar
Karolis Juodelė's user avatar
Karolis Juodelė's user avatar
Karolis Juodelė
  • Member for 12 years
  • Last seen more than a month ago
60 votes

Is there an elegant way to prove a function is linear?

23 votes

Can two topological spaces surject onto each other but not be homeomorphic?

23 votes

Is $\tan(\pi/2)$ undefined or infinity?

16 votes

Proving $\sqrt{a+\sqrt{b}}=\sqrt{m}+\sqrt{n}\iff a^{2}-b$ is a square

13 votes

Is $\mathbb R^2$ a field?

12 votes
Accepted

How come $\frac{n!}{n_1!\cdot n_2!\cdot...\cdot n_k!}$ is always an integer?

12 votes
Accepted

Where's the problem in this equation? Resulting in $4 = 5$

12 votes
Accepted

Why does $\sum\limits_{n=2}^{\infty} \frac{ 1}{ n^2 \log (n) }$ converge?

12 votes
Accepted

How to see $\sin x + \cos x$

11 votes
Accepted

how to prove Exponential is strictly positive?

11 votes
Accepted

Proving that the limit of $\root n \of {{a_1}^n + {a_2}^n + ... + {a_k}^n}$ is $\max(a_1,...a_k)$

10 votes
Accepted

limit: $u_n=\frac{1+2^2+3^3+...+n^n}{n^n}$.

9 votes

Mathematical way of determining whether a number is an integer

9 votes
Accepted

Showing that $ 1<\sin\frac{\alpha}{2}+\sin\frac{\beta}{2}+\sin\frac{\gamma}{2}$

9 votes
Accepted

"closure preserves homeomorphism"

9 votes
Accepted

Why is normalization of inequalities possible?

8 votes
Accepted

prove (by grammar or closures) that the prefix language is context free

7 votes

Are all multiplicative functions additive?

7 votes
Accepted

Need a hint: show that a subset $E \subset \mathbb{R}$ with no limit points is at most countable.

7 votes

$\sum a_n$ converges absolutely, does $\sum (a_n + \cdots + a_n^n)$ converge

6 votes
Accepted

A divisibility question involving Fermat's theorem use

6 votes
Accepted

5 black, 7 red, 9 blue, and 6 white marbles.

6 votes

Closure of a connected subset of $\mathbb{R}$ is connected?

6 votes
Accepted

Can we define the limit using only rational nos.?

6 votes
Accepted

Is : $||(a+b)^2 || \le ||a||^2+2||ab||+||b||^2$ true in any form when a,b, are elements of a space?

6 votes
Accepted

Continuous map between metric spaces

6 votes

How many positive integers $n$ are there such that $2n$ and $3n$ both perfect squares?

6 votes

Functions that are continuous only at two points?

6 votes
Accepted

Limit of a sequence $a_1=1;a_{n+1}=(n+1)(1+a_n)$

5 votes
Accepted

Alphametics Question

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